Dear All, I am purifying the His-tagged proteins ( 21Kda) using buffer 20mM Tris, 150mM Nacl, and 5mM MgCl2 with 500mM imidazole. Earlier I was facing the precipitation problem during dialysis but with the addition of 50mM L-Arg somehow managed to overcome the precipitation issue. But this time I have seen after overnight dialysis there are degradation products on SDS page. I have used protease inhibitor (PMSF) in my sonication buffer.
Please suggest me to overcome this problem. Thanks -- Anamika
